A semiconductor device known in the art is described in U.S. Patent Application Publication No. 2004/0036172. The known semiconductor device has a device housing with an integrated circuit comprising a substrate having mutually opposite top sides and undersides. Furthermore, the semiconductor device has a semiconductor chip having a rear side opposite its active top side. The semiconductor chip is mounted on the top side of the substrate in such a way that the rear side of the semiconductor chip faces the substrate. The plastic housing has a thermally conductive interposer arranged on the active top side of the semiconductor chip. A heat sink is arranged on the interposer, the heat sink projecting from the plastic housing by its top side.
In this case, the interposer forms a thermal coupling between the active top side of the semiconductor chip and the heat sink. Consequently, the function of the interposer is extremely limited, since it can neither be used as an intermediate wiring plate nor serve as an additional heat sink.
As is known, semiconductor chips generate heat loss. The latter is dissipated from the semiconductor chip via the housing, with the result that the semiconductor chip is prevented from heating up and thereby being able to be destroyed. The heat dissipation takes place as in the above document in that the semiconductor chip is connected via a good thermal conductor, such as a metal, a heat dissipater and/or a heat sink. The wiring substrate in the form of a printed circuit board on which the housing of the semiconductor device is fixed may already serve as a heat dissipater. In this case, the plastic housing composition performs the function of a thermal connection between the active top side of the semiconductor chip and the wiring substrate.
A further heat path passes directly through the semiconductor chip, such that the heat loss passes to the wiring substrate via the rear side of the semiconductor chip. For this purpose, the chip is generally mounted by its passive rear side onto a provided chip contact area of the wiring substrate. In the case of semiconductor devices which are constructed using BGA technology or using leadframeless technology, the heat can therefore principally be emitted in the direction of a printed circuit board in the form of the wiring substrate. The document cited above enables a third path for dissipating heat loss, in the case of which an interposer is arranged directly on the active top side of the semiconductor chip, and, for its part, it is thermally conductively connected to a heat sink.
In addition to the disadvantages already mentioned above that such an interposer can only be used to a limited extent, a further disadvantage arises in that a multiplicity of thermal transfers have to be provided in order to emit the power loss from the active top side of the semiconductor chip via the third heat path to the surroundings. However, the multiplicity of heat transfers restricts the effectiveness of the heat dissipation using the known means. Moreover, a function of the interposer as an intermediate wiring carrier, as is required for the stacking of semiconductor devices, cannot be fulfilled with the interposer known from the above document.